Patch "serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios()" has been added to the 4.4-stable tree

Patch "serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios()" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios()

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     serial-samsung-reorder-the-sequence-of-clock-control-when-call-s3c24xx_serial_set_termios.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From b8995f527aac143e83d3900ff39357651ea4e0f6 Mon Sep 17 00:00:00 2001
From: Chanwoo Choi <cw00.choi@samsung.com>
Date: Thu, 21 Apr 2016 18:58:31 +0900
Subject: serial: samsung: Reorder the sequence of clock control when call s3c24xx_serial_set_termios()

From: Chanwoo Choi <cw00.choi@samsung.com>

commit b8995f527aac143e83d3900ff39357651ea4e0f6 upstream.

This patch fixes the broken serial log when changing the clock source
of uart device. Before disabling the original clock source, this patch
enables the new clock source to protect the clock off state for a split second.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

---
 drivers/tty/serial/samsung.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -1263,6 +1263,8 @@ static void s3c24xx_serial_set_termios(s
 	/* check to see if we need  to change clock source */
 
 	if (ourport->baudclk != clk) {
+		clk_prepare_enable(clk);
+
 		s3c24xx_serial_setsource(port, clk_sel);
 
 		if (!IS_ERR(ourport->baudclk)) {
@@ -1270,8 +1272,6 @@ static void s3c24xx_serial_set_termios(s
 			ourport->baudclk = ERR_PTR(-EINVAL);
 		}
 
-		clk_prepare_enable(clk);
-
 		ourport->baudclk = clk;
 		ourport->baudclk_rate = clk ? clk_get_rate(clk) : 0;
 	}


Patches currently in stable-queue which might be from cw00.choi@samsung.com are

queue-4.4/serial-samsung-reorder-the-sequence-of-clock-control-when-call-s3c24xx_serial_set_termios.patch